1. Field of the Invention
The present invention relates to a novel peptide, a gene coding for the peptide, a process for production of the peptide using the gene inserted to an expression vector, and use of the peptide.
2. Description of the Related Art
A normal regulation of the blood pressure in a human body is important for the maintenance of personal health, and various physical and humoral factors contribute to this regulation of the blood vessels, etc. The humoral factors include, for example, the reninangiotensin-aldosterone system, catecholamines, prostaglandins, kinin-kallikrein system, and natriuretic hormones including ouabain-like substances. Herein the term "natriuretic" will denote selective excretion of sodium cation relating to potassium cation.
Granules morphologically similar to granules present in peptide hormone-producing cells are found in human atrium (J.D. Jamieson and G.E. Palade, J. Cell Biol., 23, 151, 1964). An extract of rat atrium and granules contained therein are known to show natriuretic action in rats (A.J. DeBold et. al., Life Science, 28, 89, 1981; R. Keeler, Can. J. Physiol. Pharmacol., 60, 1078, 1982). Recently Mark G. Currie et. al. suggested peptide-like substances with a molecular weight of 20,000 to 30,000, or not more than 10,000, present in the atrium of humans, rabbits, swine, and rats, and having natriuretic action (Science, 221, 71-73, 1983).
Moreover, a peptide consisting of 28 amino acids derived from rat atrium cordis was identified (Biochem. Biophys. Res. Commun.; vol 117, No. 3, P859-865, 1983). The present inventors found a new peptide consisting of 28 amino acids from human atrium cordis, referred to as ".alpha.-human atrial natriuretic polypeptide" and abbreviated as ".alpha.-hANP" (Biochem. Biophys. Res. Commun. Vol 118, No. 1, P 131-139, 1984, U.S. Ser. No. 685151 of the present inventors. The .alpha.-hANP has following amino acid sequence: ##STR1## wherein Cys at the 7 position and Cys at the 23 position are bonded through a disulfide bond.
Various kinds of physiologically active peptides are known to be derived in vivo from their precursors by the action of an endopeptidase or exopeptidase, rather than produced directly For example, .beta.-endorphin and .gamma.-lipotropin are derived from their precursor .beta.-lipotropin, and .beta.-melanocyte-stimulating hormone is derived from its precursor .gamma.-lipotropin (Takahashi H. et. al., FEBS Lett. 135, 97-102, 1981).